The activity budget and use of territory by a tropical blenniid fish

Both sexes of Ophioblennius atlanticus (Valenciennes) maintain permanent territories, intermixed without pattern. They occur at a density of about 1.9 individuals per m² on shallow coral rock and comprise a significant portion of the benthic fish biomass. They are diurnal; about 60% of their time is spent resting, 15% swimming and 8.5% feeding. Feeding is concentrated in the afternoon and is time-minimized. Territory is used exponentially, about 50% of time being spent in about 15% of the territory. The relatively infrequent use of peripheral parts of a territory suggest that it is potentially compressible or expansible. This, in turn, leads to a conclusion that an optimum size can only be defined as a range and mat, normally, a territory includes more resources than the minimum for survival. Competition may be reduced between aegis corrivals of different species.     

The effect of territorial damselfish (family Pomacentridae) on the space use and behaviour of the coral reef fish, Halichoeres bivittatus (Bloch, 1791) (family Labridae)

Most demersal species of damselfish (family Pomacentridae) are territorial herbivores that aggressively chase other fishes away from their nests. This study investigates whether the aggressive territorial damselfish, Stegastes leucostictus, modifies behaviours and home range area use in a less aggressive, non-territorial species, the slippery dick wrasse, Halichoeres bivittatus (family Labridae). Damselfishes and wrasses are ubiquitous and abundant members of coral reef fish assemblages around the world; hence, this study has broader implications beyond the two Caribbean species chosen for this study. A manipulative field experiment consisted of transplanting one or three S. leucostictus into artificial shelters positioned within adult or adjacent to juvenile H. bivittatus home ranges. The introduction of damselfish had little effect on the size of home range areas of juvenile or adult wrasses, but had a significant effect on the location of their home ranges. The damselfish also affected adult microhabitat use but did not affect use by juveniles. In addition, there was an increase in damselfish-wrasse interactions that resulted in a significant reduction in the amount of time adult wrasses could spend foraging or in a foraging assemblage. It was concluded that aggressive interactions with territorial damselfish affect individual H. bivittatus space use and may consequently affect the spatial distribution of H. bivittatus populations.     

The use of passive integrated transponder systems (PIT) triggered by infrared-gates for behavioural studies in nocturnal, bottom-dwelling fish species

The movements of juvenile burbot Lota lota were monitored continuously with an overall efficiency of 92·5%. The results show that passive integrated transponder (PIT) systems (or variations of them) are highly valuable for behavioural studies of small nocturnal fish species at the laboratory or mesocosm scale.     

The effect of group size on space use and aggression at a concentrated food source in blue gouramis, Trichogaster trichopterus (Pisces: Belontiidae)

Synopsis We examined how spatial distribution and the use of aggressive behavior by blue gouramis, Trichogaster trichopterus (Belontiidae), in the presence of a concentrated food source were affected by group size and by the short-term presence and absence of food. Gouramis aggregated in the area of the food source, and the frequency of aggressive acts per fish was higher for fish near the food source than for fish away from it. The frequency of aggressive acts per fish near the food source decreased with group size and was about 50 times higher in groups of 2 and 4 than it was in groups of 16 and 32. In group sizes 2 and 4, the frequency of aggression was unaffected by the presence and absence of food, but in larger group sizes aggression increased during short intervals without food. The mean proportion of time spent near the food source increased from group size 2 to group size 8 and decreased from group size 8 to group size 32 and was greater during intervals of food availability than during intervals in which food was not available. We suggest that gouramis adjust their relative use of contest and scramble competition according to the costs and benefits of aggression as determined by the number of competitors and by the potential for missed feeding opportunities. The average proportion of time spent in the vicinity of the food source appears to be influenced by both the rate of aggression and by the net rate of gain available.     

The use of gentamicin sulfate therapy in a captive blacktip reef shark (Carcharhinus melanopterus) with intestinal biting syndrome

This note reports on the use of gentamicin sulfate as a supportive measure for a juvenile blacktip reef shark (Carcharhinus melanopterus), which presented with an abrupt onset of anorexia, and laceration and prolapse of the scroll valve intestine (putative intestinal biting syndrome). Gentamicin sulfate was administered as an intramuscular injection (3.3 mg/kg body weight) every fifth day for seven treatments. The shark resumed feeding by 48 hours from the first injection, and was fully recovered by day 36. © 1993 Wiley-Liss, Inc.     

The leopardChimaera, a new species of chimaeroid fish from New Zealand (Holocephali, Chimaeriformes, Chimaeridae)

A new species ofChimaera is described from three specimens collected from deep water fishing grounds off the North Island of New Zealand at depths ranging from 327–1020 m. This species is distinguished from all other members of the genus by gray coloration with chocolate brown reticulations and spots covering the body and fins, as well as additional external features such as rounded pelvic fins, first dorsal fin with distinct white margin, preopercular and oral lateral line canals sharing a common branch, and morphology of pelvic claspers in males bifid, the distal 1/3 divided, with pale colored fleshy, distal lobes. Comparisons are made toC. monstrosa andC. owstoni, the two most similar species in the genus. this represents the first species ofChimaera to be described from New Zealand.     

The use of acetic acid as a source of carbon by cultured Chondrus crispus (Gigartinales,Rhodophyta) stackhouse

When growing seaweeds in tanks, pH and carbon source supply have to be controlled in order to maximize photosynthesis. pH can be controlled either by adding various inorganic acids which requires the extra addition of carbon, or by combining pH control and carbon source with for instance CO₂ or an organic acid such as acetic acid (CH₃COOH). We have found comparable productivity of Chondrus using CO₂ or CH₃COOH in tank culture with an increase in production of 25.0 and 27.5%, respectively, over the control. Laboratory experiments showed that acetic acid enabled us to maintain a steady state total inorganic carbon in the medium, the algae displaying an active photosynthesis. Experiments using labelled acetic acid CH₃-¹⁴COOH showed that the acid molecule or at least the -¹⁴COOH group is taken up by Chondrus although the mechanism was not elucidated. Preliminary extractions with hot ethanol showed that 67.9% of the label was solubilized from labelled tissue. Few counts were found in the carrageenans (< 1 %) and between 25.6 and 45.1% were found in the cellulosic residues. Acetic acid is suggested as an interesting means of regulating the pH and adding carbon in macrophyte culture.     

The ability of rifampin-resistant Escherichia coli to colonize the mouse intestine is enhanced by the presence of a plasmid-encoded aerobactin-iron(III) uptake system

Rifampin-resistant Escherichia coli are known to be poor colonizers of the animal intestine. In this report, we show that the colonizing ability of rifampin-resistant E. coli cells is increased dramatically in the presence of the aerobactin-mediated iron(III) uptake system. In contrast, the colonization by nalidixic acid-resistant E. coli does neither depend on the aerobactin-iron(III) nor on the dicitrate-iron(III) uptake system. Likewise, it does not depend on the production of the siderophore enterochelin.     

Photosynthetic acclimation to elevated CO2 is modified by source:sink balance in three component species of chalk grassland swards grown in a free air carbon dioxide enrichment (FACE) experiment

Artificial chalk grassland swards were exposed to either ambient air or air enriched to 600 μ mol mol^–1 CO₂, using free-air CO₂ enrichment technology, and subjected to an 8 week simulated grazing regime. After 14 months of treatment, ribulose-1,5-bisphosphate carboxylase (Rubisco) activity ( V _c,max) and electron transport mediated ribulose-1,5-bisphosphate (RuBP) regeneration capacity ( J _max), estimated from leaf gas exchange, were significantly lower in fully expanded leaves of Anthyllis vulneraria L. (a legume) and Sanguisorba minor Scop. grown in elevated CO₂. After a change in source:sink balance brought about by defoliation, photosynthetic capacity was fully restored in A. vulneraria and S. minor, but acclimation continued in the grass Bromopsis erecta (Hudson) Fourr. Changes in net photosynthesis ( P _n) with growth at elevated CO₂ ranged from a 1·6% reduction in precut leaves of A. vulneraria to a 47·1% stimulation in postcut leaves of S. minor . Stomatal acclimation was observed in leaves of A. vulneraria (reduced stomatal density) and B. erecta (reduced stomatal conductance). The results are discussed in terms of whole-plant resource-use optimization and chalk grassland community competitive interactions at elevated CO₂.     

Amino acids as a nitrogen source for tomato seedlings: The use of dual-labeled (C, N) glycine to test for direct uptake by tomato seedlings

Direct uptake of organic nitrogen (ON) compounds, rather than inorganic N, by plant roots has been hypothesized to constitute a significant pathway for plant nutrition. The aim of this study was to test whether tomatoes (Solanum lycopersicum cv. Huying932) can take up ON directly from the soil by using ¹⁵NH₄Cl, K¹⁵NO₃, 1, 2-¹³C₂¹⁵N-glycine labeling techniques. The ¹³C and ¹⁵N in the plants increased significantly indicating that a portion of the glycine-N was taken up in the form of intact amino acids by the tomatoes within 48 h after injection into the soil. Regression analysis of excess ¹³C against excess ¹⁵N showed that approximately 21% of the supplied glycine-N was taken up intact by the tomatoes. Atom% excesses of ¹⁵N and ¹³C in the roots were higher than in any shoots. Results also indicated rapid turnover of amino acids (e.g., glycine) by soil microorganisms, and the poor competitive ability of tomatoes in absorbing amino acids from the soil solution. This implies that tomatoes can take up ON in an intact form from the soil despite the rapid turnover of organic N usually found under such conditions. Given the influence of climatic change and N pollution, further studies investigating the functional ecological implications of ON in horticultural ecosystems are warranted.     

The centipede genus Eupolybothrus Verhoeff, 1907 (Chilopoda: Lithobiomorpha: Lithobiidae) in North Africa, a cybertaxonomic revision, with a key to all species in the genus and the first use of DNA barcoding for the group

The centipede genus Eupolybothrus Verhoeff, 1907 in North Africa is revised. A new cavernicolous species, Eupolybothruskahfi Stoev & Akkari, sp. n., is described from a cave in Jebel Zaghouan, northeast Tunisia. Morphologically, it is most closely related to Eupolybothrusnudicornis (Gervais, 1837) from North Africa and Southwest Europe but can be readily distinguished by the long antennae and leg-pair 15, a conical dorso-median protuberance emerging from the posterior part of prefemur 15, and the shape of the male first genital sternite. Molecular sequence data from the cytochrome c oxidase I gene (mtDNA-5' COI-barcoding fragment) exhibit 19.19% divergence between Eupolybothruskahfi and Eupolybothrusnudicornis, an interspecific value comparable to those observed among four other species of Eupolybothrus which, combined with a low intraspecific divergence (0.3-1.14%), supports the morphological diagnosis of Eupolybothruskahfi as a separate species. This is the first troglomorphic myriapod to be found in Tunisia, and the second troglomorph lithobiomorph centipede known from North Africa. Eupolybothrusnudicornis is redescribed based on abundant material from Tunisia and its post-embryonic development, distribution and habitat preferences recorded. Eupolybothruscloudsley-thompsoni Turk, 1955, a nominal species based on Tunisian type material, is placed in synonymy with Eupolybothrusnudicornis. To comply with the latest technological developments in publishing of biological information, the paper implements new approaches in cybertaxonomy, such as fine granularity XML tagging validated against the NLM DTD TaxPub for PubMedCentral and dissemination in XML to various aggregators (GBIF, EOL, Wikipedia), vizualisation of all taxa mentioned in the text via the dynamically created Pensoft Taxon Profile (PTP) page, data publishing, georeferencing of all localities via Google Earth, and ZooBank, GenBank and MorphBank registration of datasets. An interactive key to all valid species of Eupolybothrus is made with DELTA software.